Field-Modulated Redistribution Mechanism of Trapped Charges From TID Irradiation and Experiments in SJ-LDMOS

A novel field-modulated redistribution (FR) mechanism of trapped charges from total ionizing dose (TID) irradiation is proposed and experimentally demonstrated in this article. The FR mechanism reveals the redistribution dynamics of irradiation-induced trapped charges at the Si/SiO₂ interface of high-voltage superjunction lateral double-diffused metal–oxide semiconductor (SJ-LDMOS), subject to varying electric field distributions resulting from different Drain biases. The lateral component of the electric field leads to the transport of irradiation-induced holes in the voltage-withstanding direction, while the vertical component facilitates the extraction of irradiation-induced holes. Ultimately, the movement of holes leads to the positive trapped charges are primarily located in the middle of the voltage-withstanding layer and vary with different applied biases. Based on the FR mechanism, a 700 V level SJ-LDMOS, which incorporates a source-side stepped field plate serving as a vertical field extraction structure, was designed and manufactured. The experiments demonstrated an irradiation withstand performance surpassing 150 krad(Si), corresponding to a condition where the channel remains permanently open. Under high voltage bias, the device exhibited an increase in breakdown voltage V_B from an initial 750 V to about 785 V, accompanied by about 5% enhancement in current capability. This device demonstrates potential application in aerospace and deep-space exploration electronic systems.